Primarily, it removes the strange "make_META.pl" symlink behavior. It
is not at all clear to me why the symlink was being generated on the fly,
and then version_tag.pl changed its behavior based on its name. Odd.

Instead version_tag.pl now take "--make_META" as the first option on
its command line.

Further, we haven't use CVS in a long time, so this patch removes
the cvs-related file and checks.

The is_git and is_cvs variables weren't even used, so those are removed
as well.